KR20170140920A - Reverse osmosis membrane apparatus for energy saving and water treating method using the same - Google Patents

Abstract

The present invention relates to a reverse osmosis membrane device and a water treatment method using the same. More specifically, the present invention relates to an energy saving reverse osmosis membrane device, and a water treatment method using the same. To this end, the reverse osmosis membrane device comprises: a pressure container treating treatment water; a plurality of reverse osmosis membrane elements provided in the pressure container; and an interconnector provided between the plurality of reverse osmosis membrane elements, and controlling a flux of the treatment water.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reverse osmosis membrane device for energy saving and a water treatment method using the reverse osmosis membrane device,

The present invention relates to a reverse osmosis membrane device and a water treatment method using the reverse osmosis membrane device, and more particularly, to a reverse osmosis membrane device capable of energy saving and a water treatment method using the reverse osmosis membrane device.

Seawater desalination technology has been proposed as a solution to providing alternative water resources to domestic water-scarce areas, which is a representative technology field that can solve the global water shortage problem, provide alternative water resources securing technology, and generate high added value. , It has the advantage of reducing costs and improving environmental problems by replacing water conservation measures through dam construction, which is controversial for environmental problems.

The seawater desalination method can be largely divided into the evaporation method and the reverse osmosis method, and the reverse osmosis method is widely used because the reverse osmosis method requires a relatively small amount of energy to produce a unit volume of water as compared with the evaporation method. The reverse osmosis method separates the components contained in seawater or sea water into product water and concentrated water using a reverse osmosis membrane (reverse osmosis membrane) (reverse osmosis membrane). The product water is used as water and drinking water by diluting the component concentration, Is discharged to the sea again.

The seawater desalination or desalination apparatus using a reverse osmosis membrane (hereinafter also referred to as RO (Reverse Osmosis) membrane) uses reverse osmosis pressure, and therefore, as shown in FIG. 1, a plurality of RO membranes The elements 101 are arranged in series and each RO membrane element 101 is connected to the water collection pipe 102 at the center of the RO membrane element 101.

The supply water or the water to be treated is pressurized inside the pressure vessel 100 by opening and closing the valve 103 provided on the concentrated water side by the high pressure pump 104 from one side of the desalination apparatus. When the pressurized pressure exceeds the osmotic pressure of the feed water, the feed water or the untreated water passes through the RO membrane and the desalted water (permeate) flows into the central water collection pipe 102.

The supply pressure of the supply water supplied into the pressure vessel 100 becomes higher and the pressure becomes lower as the permeation progresses from the supply water side. Therefore, the pressure applied to the pressure vessel 100 becomes higher than the salt concentration of the final discharge water And the feed flow rate, the feed rate of the film surface, and the like.

Therefore, since the pressure is applied to the water supply side in the pressure vessel 100 more than necessary, the permeation water amount increases. For example, the relationship between the position of the RO membrane element and the relative flux (relative flux) when seven RO membrane elements 101a are arranged in series as shown in Fig. 2 is shown in Fig. 3, Means the position of the RO membrane element from the water side.

As can be seen from FIG. 3, the permeation rate of the feed water is large, and the filtration by the RO membrane is continued and concentration is progressed. This is because the salt concentration of the concentrated water becomes higher as the treatment water is treated by the RO membrane in the pressure vessel 100 and a high pressure is required for filtration by the RO membrane in the concentrated water of high concentration, This is because the permeation flow rate of the RO membrane is relatively reduced as compared with the inlet side to which the feed water is supplied.

As shown in FIG. 2, when the RO membrane elements are arranged in series in the pressure vessel 100, flux is concentrated in the first RO membrane to cause flux over, and the pressure vessel 100 The amount of energy required to increase the pressure is increased, and the RO membrane element on the supply water is contaminated more rapidly.

In order to solve this problem, as shown in FIG. 4, a hybrid reverse osmosis membrane device in which one to three middle fluxes or low flux reverse osmosis membranes are mixed in a lead membrane region at the upstream end of a pressure vessel However, due to the mixing of the middle flux or the low flux reverse osmosis membrane, the pressure to be added to the water to be treated is relatively increased by using the high pressure pump, and relatively energy saving effect Is reduced. As shown in FIG. 5, the pressure vessel is divided into two stages, and a flow control valve is installed in the permeate line of the first stage to adjust the amount of flux, A reverse osmosis membrane device has been proposed. However, the pressure vessel is divided into two stages to increase the rack size and piping connection quantity, resulting in an increase in CAPEX (Capital Expenditures).

Accordingly, development of a reverse osmosis membrane device for energy saving is required.

Korean Patent Registration No. 10-1189006

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is an object of the present invention to provide a method of controlling a flow rate in a pressure vessel by using an interconnector to prevent flux over, And a water treatment method using the same.

These and other objects and advantages of the present invention will become apparent from the following description of a preferred embodiment.

The object is achieved by a pressure vessel for treating water to be treated; A plurality of reverse osmosis membrane elements provided inside the pressure vessel; And an inter connector provided between the reverse osmosis membrane element and for controlling the flow rate of the water to be treated.

At this time, the pressure vessel is one, and the treated water can be treated in a single stage.

The plurality of reverse osmosis membrane elements may include a high flux reverse osmosis membrane having a flux of 1.7 to 2.7 m 3 / hr, and the plurality of reverse osmosis membrane elements may be connected in series.

Further, the interconnector may be provided with an orifice ring at an inlet through which the for-treatment water is supplied or an outlet through which the for-treatment water is discharged.

The object of the present invention can also be achieved by a method for treating an ozone depleted product, comprising: supplying water to be treated to a pressure vessel having a plurality of reverse osmosis membrane elements therein; And controlling the flow rate of the water to be treated by using an interconnector provided between the reverse osmosis membrane element and the water treatment method using the reverse osmosis membrane device.

At this time, the pressure vessel is one, and the treated water can be treated in a single stage.

The plurality of reverse osmosis membrane elements may include a high flux reverse osmosis membrane having a flux of 1.7 to 2.7 m 3 / hr, and the plurality of reverse osmosis membrane elements may be connected in series.

Further, the interconnector may be provided with an orifice ring at an inlet through which the for-treatment water is supplied or an outlet through which the for-treatment water is discharged.

According to the present invention, it is possible to prevent the flux over of the reverse osmosis membrane device by controlling the amount of permeation using the interconnector, and to have an energy saving effect.

Specifically, there is no need to use a middle flux or a low flux reverse osmosis membrane in combination, and there is no need to increase the pressure to be applied to the water to be treated, and there is no need to divide the pressure vessel into two stages, piping connection can reduce capital expenditure (CAPEX).

However, the effects of the present invention are not limited to the above-mentioned effects, and other effects not mentioned can be clearly understood by those skilled in the art from the following description.

1 is a schematic cross-sectional view of a pressure vessel having a reverse osmosis membrane element.
2 is a schematic illustration of a reverse osmosis membrane device in which reverse osmosis membrane elements are connected in series in one pressure vessel.
FIG. 3 is a graph showing changes in flux when the reverse osmosis membrane device of FIG. 2 is used.
4 is a schematic view of a conventional hybrid reverse osmosis membrane device according to an example.
FIG. 5 is a schematic illustration of a conventional two-stage reverse osmosis membrane device according to one example.
6 is a schematic illustration of a reverse osmosis membrane device including an interconnect according to one embodiment of the present invention.
FIG. 7A is a schematic view of an inter connector having an orifice ring according to an exemplary embodiment of the present invention, and FIG. 7B is a view schematically showing connection of an inter connector with reverse osmosis membrane elements.

Hereinafter, the present invention will be described in detail with reference to embodiments and drawings of the present invention. It will be apparent to those skilled in the art that these embodiments are provided by way of illustration only for the purpose of more particularly illustrating the present invention and that the scope of the present invention is not limited by these embodiments .

Also, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains and, where contradictory, Will be given priority.

In order to clearly illustrate the claimed invention, parts not related to the description are omitted, and like reference numerals are used for like parts throughout the specification. And, when a section is referred to as "including " an element, it does not exclude other elements unless specifically stated to the contrary. In addition, "part" described in the specification means one unit or block performing a specific function.

In each step, the identification code (first, second, etc.) is used for convenience of explanation, the identification code does not describe the order of each step, and each step does not explicitly list a specific order in the context May be performed differently from the above-described sequence. That is, each of the steps may be performed in the same order as described, or may be performed substantially concurrently or in the reverse order.

6 is a schematic illustration of a reverse osmosis membrane device including an interconnect according to one embodiment of the present invention. Referring to FIG. 6, the reverse osmosis membrane device according to one embodiment of the present invention includes a pressure vessel 100 for treating water to be treated; A plurality of reverse osmosis membrane elements 101 provided inside the pressure vessel 100; And an interconnector (200) provided between the reverse osmosis membrane element (101) and the flow rate of the water to be treated. Specifically, a plurality of reverse osmosis membrane elements 101 are installed in a cylindrical pressure vessel 100, a water collecting pipe 102 is installed at the center of the pressure vessel 100, and connected to each of the reverse osmosis membrane elements 101, And an inter connector 200 capable of controlling the flow rate of the water to be treated between the elements 101, and a high-pressure pump 104 for supplying the water to be treated. The to-be-treated water is supplied into the pressure vessel 100 by the high-pressure pump 104. When the pressurized pressure exceeds the osmotic pressure of the for-treatment water, the for-treatment water passes through the reverse osmosis membrane and flows into the water collecting pipe 102 Demineralized water (treated water) is collected.

As shown in FIGS. 2 and 3, when the RO membrane having a high flux is connected in series as a single step (one pressure vessel) as in the conventional reverse osmosis membrane device, the permeability irregularity The first to third reverse osmosis membrane elements adjacent to the for-treatment water inlet portion 105, which are positioned in the lead-in water introducing portion 105 side of the RO membrane module connected in series in the pressure vessel 100, ), Excessive membrane filtration occurs due to excessively large amount of filtration (flux over), so that frequent cleaning / maintenance of the apparatus is required. In order to maintain the total pressure in the pressure vessel 100 Higher pressure is required, leading to higher operating costs.

In order to solve this problem, a hybrid type membrane device or pressure vessel 100 using a low flux RO membrane 101b instead of the high flux RO membrane 101a in the lead membrane area as shown in FIG. stage, but this structure has not yet achieved the energy saving effect sufficiently. Specifically, the hybrid method shown in FIG. 4 has an advantage that the degree of film contamination of the lead membrane area can be reduced. However, since the pressure to be applied to the water to be treated in the pressure vessel 100 is relatively high, 5, the first pressure vessel 100 and the second pressure vessel 100 'are provided. In the case of the two-step system in which the first pressure vessel 100 and the second pressure vessel 100' are provided, The flow rate control valve 103 is provided in the permeated water discharge pipe to control the discharge flow rate of the treated water subjected to the primary treatment by the RO membrane element 101, It is necessary to increase the pressure to be applied to the water to be introduced into the first pressure vessel 100 due to the operation of the flow rate control valve 103, The problem of relatively high energy consumption can not be solved fundamentally.

Accordingly, the present invention can prevent the flux over of the reverse osmosis membrane device without significantly changing the main constitution (pressure vessel, reverse osmosis membrane, etc.) of the conventional reverse osmosis membrane device, In order to improve the saving effect, the amount of permeation is adjusted by using the inter connector 200.

The interconnector 200 is provided between the reverse osmosis membrane element 101 and controls the flow rate of the water to be treated so that the back pressure required for the flow rate control is controlled within the pressure vessel 100 . In order to control the flow rate using the inter connector 200, the thickness of the inter connector 200 may be adjusted or an orifice ring 201 (not shown) may be attached to the inlet (for-treated water supply) (orifice ring) can be used. 7A is a schematic view of an inter connector 200 with an orifice ring 201 according to an embodiment of the present invention. FIG. 7B schematically shows an inter connector 200 connected between reverse osmosis membrane elements 101 Referring to FIG. 3, the interconnector 200 may be formed in a cylindrical shape, and the upper surface and the lower surface may be opened to allow the for-treatment water to move. The orifice ring 201 is coupled to the upper surface or the lower surface of the orifice ring 201 and may be connected to the orifice ring 201 having various sizes according to the purpose. .

The interconnector 200 further includes a reverse osmosis membrane element 101 of the lead membrane region (the first through third reverse osmosis membrane elements adjacent to the to-be-treated water inlet portion in FIG. 6) in order to prevent unnecessary use of materials and maximize the energy saving effect. As shown in Fig. That is, between the first to third reverse osmosis membrane elements 101 adjacent to the to-be-treated water introducing portion 105 to which the for-treatment water is supplied.

In one embodiment, the pressure vessel 100 is cylindrical and has a plurality of reverse osmosis membrane elements 101 and a water collecting pipe 102 therein. The water vessel 100 has a to-be- A treated water discharging portion 107 for discharging the treated water collected in the water collecting pipe 102, and a concentrated water discharging portion 106 for discharging the concentrated untreated water. Preferably, the pressure vessel 100 is one, and the treated water can be treated in a single stage. By controlling the amount of permeation using the interconnector 200, the present invention can reduce the flux over and save energy even if it is constituted in a single step like the conventional reverse osmosis membrane device.

In one embodiment, the plurality of reverse osmosis membrane elements 101 may include a high flux reverse osmosis membrane 101a having a flux of 1.7 to 2.7 m3 / hr, and may be connected in series. The number of the reverse osmosis membrane elements 101 may be seven, but the present invention is not limited thereto, and more or less may be used depending on the purpose. In general, the RO membrane is treated with a high flux (1.7 to 2.7 m3), depending on the flow rate of the produced water, under standard test conditions (Feed Water TDS: 32,000 ppm as NaCl, Feed Pressure: 55.2 bar, Recovery Ratio: / hr RO membrane 101a, a middle flux (1.4 m 3 / hr) RO membrane and a low flux (0.96-1.2 m 3 / hr) RO membrane 101b. The relatively low supply pressure it is advantageous to use the high flux RO membrane 101a in that it can be produced at a feed pressure.

Next, a water treatment method using a reverse osmosis membrane device will be described. In describing the water treatment method, the reverse osmosis membrane device described above will be mainly described, and a redundant description related to the reverse osmosis membrane device will be omitted. However, this is for the sake of explanation only, but the present invention is not limited thereto.

According to an aspect of the present invention, there is provided a water treatment method using a reverse osmosis membrane device, comprising: supplying water to be treated to a pressure vessel having a plurality of reverse osmosis membrane elements therein; And controlling the flow rate of the water to be treated by using the inter connector 200 provided between the reverse osmosis membrane elements.

The present invention relates to a water treatment method or a pressure vessel 100 using a hybrid type reverse osmosis membrane apparatus using a conventional high flux RO membrane 101a and a low flux or middle flux RO membrane in combination, Unlike the water treatment method using a reverse osmosis membrane membrane type apparatus that applies a back pressure, a back pressure is controlled in the pressure vessel 100 by controlling the flow rate of water to be treated by using an inter connector 200 disposed between the reverse osmosis membrane elements It is possible to prevent the flux-over of the lead membrane region and to save energy.

Hereinafter, the structure and effect of the present invention will be described in more detail with reference to examples and comparative examples. However, this embodiment is intended to explain the present invention more specifically, and the scope of the present invention is not limited to these embodiments.

[Example]

In the pressure vessel, seven reverse osmosis membrane elements including a high flux reverse osmosis membrane (XLE-440i, Filmtec) are connected in series, and an orifice ring is interposed between the first reverse osmosis membrane element and the second reverse osmosis membrane element, A reverse osmosis membrane device in which an interconnect is disposed.

[Comparative Example]

A reverse osmosis membrane device was prepared in which two low flux reverse osmosis membranes (XHR-440i, Filmtec) and five high flux reverse osmosis membranes (XLE-440i, Filmtec) were serially connected in series in the pressure vessel.

[Experimental Example]

For each of the reverse osmosis membrane devices of the Examples and Comparative Examples, computer simulation was performed using Toray Design System 2.0, which is a commercial RO Projection program, while changing some conditions (temperature and operating years), and energy reduction effects were compared. The results are shown in Table 1 below.

[Table 1]

As can be seen from the above Table 1, in the embodiment in which the amount of permeation was adjusted by using the interconnector, the total energy saving effect was 1.6 to 2.4% as compared with the comparative example of the hybrid type. Specifically, the reverse osmosis membrane has a different flux and salt permeability depending on the temperature of the influent and the operating year. It exhibits low flux and high salt permeability at low temperature and high flux and low salt permeability at high temperature. Also, as the coefficient of performance (FF, 0.8 at 1 and 5 years operation at the start of operation) increases (the number of years of operation increases), the flux decreases and the salt permeability increases. Cases 1 to 4 of the examples and comparative examples were obtained by comparing the performance of the minimum / maximum temperature of the operating conditions and the performance at the start of operation / limit of operation. The average of each case was calculated and the energy Savings can be confirmed.

It is to be understood that the present invention is not limited to the above embodiments and various changes and modifications may be made by those skilled in the art without departing from the spirit and scope of the invention.

100, 100 ': Pressure vessel 101: RO membrane element
101a: high flux RO film 101b: low flux RO film
102: collecting pipe 103: valve
104: high-pressure pump 105:
106: concentrated water discharging part 107: treated water discharging part
108: ERD (energy recovery device) pump 109: Energy recovery device (ERD)
200: Interconnector 201: Orifice ring

Claims (10)

A pressure vessel for treating the for-treatment water;
A plurality of reverse osmosis membrane elements provided inside the pressure vessel; And
And an inter connector provided between the reverse osmosis membrane elements for controlling the flow rate of the water to be treated. The method according to claim 1,
Characterized in that the pressure vessel is one, and the treated water is treated in a single stage. The method according to claim 1,
Wherein the plurality of reverse osmosis membrane elements comprise a high flux reverse osmosis membrane having a flux of 1.7 to 2.7 m 3 / hr. The method according to claim 1,
Wherein the plurality of reverse osmosis membrane elements are connected in series. The method according to claim 1,
Wherein the interconnector is provided with an orifice ring at an inlet through which the for-treatment water is supplied or an outlet through which the for-treatment water is discharged. Supplying water to be treated to a pressure vessel having a plurality of reverse osmosis membrane elements therein; And
And controlling the flow rate of the water to be treated by using an interconnector provided between the reverse osmosis membrane elements. The method according to claim 6,
Wherein one of the pressure vessels is treated as a single step with the water to be treated. The method according to claim 6,
Wherein the plurality of reverse osmosis membrane elements comprise a high flux reverse osmosis membrane having a flux of 1.7 to 2.7 m 3 / hr. The method according to claim 6,
Wherein the plurality of reverse osmosis membrane elements are connected in series. The method according to claim 6,
Wherein the interconnector is provided with an orifice ring at an inlet through which the for-treatment water is supplied or an outlet through which the for-treatment water is discharged.

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